Diagnostic accuracy and acceptability of molecular diagnosis of COVID-19 on saliva samples relative to nasopharyngeal swabs in tropical hospital and extra-hospital contexts: The COVISAL study

PLoS One. 2021 Sep 13;16(9):e0257169. doi: 10.1371/journal.pone.0257169. eCollection 2021.

Abstract

A prospective study was conducted among different intra and extra-hospital populations of French Guiana to evaluate the performance of saliva testing compared to nasopharyngeal swabs. Persons aged 3 years and older with mild symptoms suggestive of COVID-19 and asymptomatic persons with a testing indication were prospectively enrolled. Nasopharyngeal and salivary samples were stored at 4°C before analysis. Both samples were analyzed with the same Real-time PCR amplification of E gene, N gene, and RdRp gene. Between July 22th and October 28th, 1159 persons were included, of which 1028 were analyzed. When only considering as positives those with 2 target genes with Ct values <35, the sensitivity of RT-PCR on saliva samples was 100% relative to nasopharyngeal samples. Specificity positive and negative predictive values were above 90%. Across a variety of cultures and socioeconomic conditions, saliva tests were generally much preferred to nasopharyngeal tests and persons seemed largely confident that they could self-sample. For positive patients defined as those with the amplification of 2 specific target genes with Ct values below 35, the sensitivity and specificity of RT-PCR on saliva samples was similar to nasopharyngeal samples despite the broad range of challenging circumstances in a tropical environment.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • COVID-19 Nucleic Acid Testing / methods*
  • COVID-19 Nucleic Acid Testing / standards
  • Child
  • Child, Preschool
  • Female
  • French Guiana
  • Hospitals / statistics & numerical data
  • Humans
  • Male
  • Middle Aged
  • Nasopharynx / virology
  • Patient Acceptance of Health Care
  • Saliva / virology*
  • Sensitivity and Specificity
  • Tropical Climate

Grants and funding

The project was funded by the Ministère de l’Enseignement Supérieur et de la Recherche (N° EJ 2103081499).